Methods and Apparatus for Preparing a Dental Implant Site

ABSTRACT

A dental implant site preparation tool ( 10 ) includes a shaft ( 12 ) and a working end ( 14 ). The working end includes a cutting surface ( 16 ) that includes cutting features. The working end ( 14 ) also includes a substantially smooth tip ( 18 ) that may have a convex shape. A method of preparing a dental implant site includes working the tool ( 10 ) so as to create a shape that matches that of an implant.

CROSS-REFERENCE TO RELATED APPLICATION AND PRIORITY INFORMATION

This application claims the benefit of co-pending, prior filed U.S.provisional application No. 61/949,908, entitled “Eccentric DentalImplant System and Toggle Burr”, filed Mar. 7, 2014.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to dentistry, and more particularly tomethods and apparatus for preparing a dental implant site.

BACKGROUND OF THE INVENTION

In recent years, the use of dental implants has become widespread.Concentrically shaped implants are the most common, and offer relativelyeasy installation. Their round shape allows the use of conventionaldrills and screwing techniques. However, well known functional,hygienic, and aesthetic problems can be associated with concentricimplants.

Eccentrically shaped implants, which more closely match natural teethshapes, may reduce such problems. However, eccentric implants are oftenmore difficult to install than concentric implants, partly due to thedifficulty of preparing eccentric osteotomies, which sometimes requirespecial instrumentation. For example, some eccentric implants employ aneccentric base, which must be implanted into a prepared site in thejawbone. Improper preparation of the site can lead to significantproblems.

In particular, if the implant site is not properly prepared, the implantmay not integrate with the jawbone with sufficient strength to provideadequate stability. As examples of poor implant sites, the site may betoo large, or too deep, or too shallow, or too tapered, or mismatched tothe shape of the implant, leading to voids or insufficientjawbone-to-implant surface contact, or to hygienic or aestheticproblems. Relatedly, if the implant site is too deep or too tapered,there may be insufficient bone mass available for adequately securing animplant anchor.

Therefore, a need has arisen for improved methods and apparatus forpreparing dental implant sites.

SUMMARY OF THE INVENTION

In accordance with the teachings of the present invention, methods andapparatus for preparing dental implant sites are provided that eliminateor substantially reduce problems associated with prior art systems.

In a particular embodiment, an apparatus for preparing a dental implantsite in a jawbone is provided which comprises an osteotomy seat having aworking surface and a burr having a shaft with a working end. Theworking end comprises a cutting surface and a smooth tip for contactwith the working surface.

Also provided is a method of preparing a dental implant site in ajawbone, which includes forming an osteotomy site in a bone, the sitehaving a bottom and sidewalls, placing an osteotomy seat on the bottomof the osteotomy, and working a burr upon the osteotomy seat to widenthe osteotomy site by cutting the sidewalls.

Working may include toggling the burr, vibrating the burr, rotating theburr, reciprocating the burr, or any combination of one or more of thesemotions.

Also provided is an instrument for preparing a dental implant site in ajawbone that comprises a shaft having a working end. The working endcomprises a cutting surface and a smooth tip. A vibrational source iscoupled to the shaft.

Also provided is an instrument for preparing a dental implant site in ajawbone that comprises a shaft having a working end. The working endincludes a cutting surface and a smooth tip, wherein the smooth tip isbroad enough so as to prevent the creation of excessive depressions inthe jawbone when the smooth tip is in forced contact with the jawbone.

In another embodiment, an instrument for preparing a dental implant sitein a jawbone is provided which comprises a shaft having a working endwith a cutting surface. A pivot member is coupled to the working end,and an extension is engaged with the pivot member, such that the workingend pivots on the extension.

An important technical advantage of the invention is that it providesfor predictably accurate eccentric preparation of the bone. Inparticular, the smooth tip of the burr prevents cutting the bottom ofthe osteotomy site, thereby preventing any substantial damage oralteration of the bottom of the site. This helps ensure that, amongother things, sufficient jawbone exists for stable anchoring of animplant. Also, the osteotomy seat and extensions provide a stableplatform on which a burr can be worked, and isolates the bottom of theosteotomy site from direct contact with the burr to further preventdamage to the bottom of the osteotomy site. Also, by coupling the burrto a vibrational source, very accurate site widening can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made in the description to the following briefly describeddrawings, which are not drawn to scale, with certain features enlargedfor clarity, in which like reference numerals indicate like features:

FIG. 1 is a schematic perspective diagram of a burr according to theteachings of the present invention; and

FIGS. 2 and 3 illustrate use of a burr according to the teachings of thepresent invention;

FIGS. 4-7 illustrate front views of various embodiments of burrsaccording to the teachings of the present invention;

FIG. 8 is a cross-sectional view of another embodiment of a burraccording to the teachings of the present invention;

FIG. 9 illustrates a perspective view of a toggle burr and osteotomyseat according to the teachings of the present invention;

FIG. 10 illustrates a perspective view of an insertion and removal toolfor an osteotomy seat according to the teachings of the presentinvention;

FIG. 11 illustrates another embodiment of a burr according to theteachings of the present invention; and

FIGS. 12-15 illustrate details of the burr of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, burr 10 includes a shaft 12 and a working end 14.Shaft 12 may include a latch (or any other suitable attachment feature,such as, without limitation, a threaded male/female joint) for couplingto and uncoupling from a tool (shown schematically as reference 15) thatrotates and/or toggles and/or vibrates the burr. For example, andwithout limitation, the shaft may be coupled to a drill for rotation, orto any suitable vibration generator (such as a piezoelectric orultrasound unit). Also, the burr 10 may be hand-manipulated without atool. In such a case, the shaft 12 may be attached to a hand piece, orsized for use with a surgeon's hand, and may include grip features.Shaft 12 may be any suitable shape in cross section, whether round oreccentric.

The working end 14 includes cutting surface 16, and a substantiallysmooth tip 18. Cutting surface 16 does not extent to the smooth tip 18.In use, working of the burr results in the cutting surface 16 cuttinginto the jawbone to widen the osteotomy site (substantially laterally)in order to create the desired shape of the eccentric implant site. Thesmooth tip 18, because it is not a cutting surface, will not cause anysubstantial deepening or broadening of the site while the burr is workedto widen the site. Thus, the smooth tip 18 helps ensure that, amongother things, sufficient jawbone exists for stable anchoring of animplant.

Preferably, the widest cross section of the burr is no broader than theminimum outside dimension of the implant for which the osteotomy site isbeing prepared. For example, if the plan view of the implant is oval(thus there is a minimum and a maximum outside diameter), the burr ispreferably no broader than the minimum diameter. Furthermore, the smoothtip 18 is preferably rounded, but may be flat. Also, to minimize damageto the bottom of the osteotomy site, it is it is preferred that the tip18 be relatively broad, and not protrude in a narrow point that couldpuncture or create depressions in the bottom of the site when the burris in forced contact with the site (i.e., while the burr is worked).

Any suitable heights (with the long axis of the shaft being consideredvertical) for the cutting surface 16 and the tip 18 may be chosen, asappropriate for the application.

As an example of one particular use of the burr 10, which is shown inFIG. 2, the working end 14 is inserted into a primary implant osteotomy(hole or site) 20 that has been formed in bone 22. For generalreference, the site 20 is considered to have a bottom 23 and sidewalls25. The burr 10 is then worked (by rotation, reciprocation, vibration,and/or toggling (and/or any other suitable motion)), and the cuttingsurface 16 cuts into bone sections 24 of bone 22 to create the desired(often eccentric) shape for receiving the implant. Because the tip 18 ofthe burr 10 is smooth, the tip 18 will not cut or substantially deepenor broaden the primary implant osteotomy site 20.

As shown in FIG. 3 (a top view of FIG. 2), as the burr 10 is worked,sections 24 of bone 22 are cut away to form whatever shaped is desired,whether concentric or eccentric, to accommodate various implantpatterns. The particular shape shown in FIG. 3 is a soft triangularshape. In this way, the site is prepared to match the shape of anyimplant, including eccentrically shaped implants.

The working end 14 may be formed of any suitable material, including,without limitation, any surgical metal or ceramic, and the cuttingsurface 16 may include any suitable cutting features and patterns. Also,the cutting surface may comprise diamond (or other material) grit of anyappropriate coarseness or any suitable roughened surface. The smooth tip18 may be of any suitable material, including, without limitation, anysurgical metal, nylon, or an appropriate ceramic material (which mayreduce friction and heat), and have any suitable surface contour,preferably convex.

FIGS. 4-7 illustrate particular examples for the working end 14. FIG. 4shows a cylindrical working end 14, with stippling used to indicatecutting surface 16 (as discussed above, any suitable cutting surface maybe used). FIG. 5 illustrates a conical working end 14. FIG. 6illustrates a working end 14 having a concave contour, and FIG. 7illustrates a working end 14 with a convex contour. These are particularexamples, and any suitable shape and surface may be used.

The smooth tip 18 may be integral with the working end 14.Alternatively, the smooth tip 18 may be an attachment that is coupled tothe working end 14. Attachment may be made in any suitable way. Forexample, and without limitation, attachment may be via a snap fit orthrough threaded engagement, or may be via a ball-bearing fitment orother suitable mechanism so that the tip 18 does not necessarily rotatewith the cutting surface 16.

The working end 14 may be formed integrally with the shaft 12, or may beattached to the shaft 12, for example (and without limitation) bythreaded engagement. As shown in FIG. 8, which is a cross sectional viewof an unassembled toggle burr 26, the working end 14 may be formed byattaching a sleeve 28 to end 30. Sleeve 28 and end 30 may be threaded toallow their coupling. Sleeve 28 may have any desired shape, as discussedabove in connection with FIGS. 4-7, and includes the cutting surface 16.The diameter of end 30 may be less than, equal to, or greater than thatof shaft 12 above the end 30. In the example shown, the diameter of end30 is greater than that of shaft 12. End 30 may be formed integrallywith shaft 12 or attached by any suitable technique.

Also shown in FIG. 8 is a threaded bore 32, which may be used to attachsmooth tip 18. However, no such bore is required because tip 18 may beformed integrally with or otherwise attached to the burr or the workingend 14 or the sleeve 28.

Whether integral or attached, the tip 18 may be elongated, or include anextension, to allow lateral cutting to be maintained at a desiredvertical distance from the bottom of the osteotomy, helping to maximizeavailable bone depth for anchoring of the implant. In one embodiment,the attachable tip 18 may be disposable.

Furthermore, a surgical guide stop or stent (which may be a hollowcylinder or cone, a plate, or any suitable boundary) may be placed overor adjacent the implant site to limit the movement of the burr 10,thereby limiting lateral cutting and the size of the osteotomy.

Burrs according to the present invention may be placed directly into anosteotomy site to form the desired shape. However, another aspect of thecurrent invention is an osteotomy seat upon which the burr is worked.

As shown in FIG. 9, an osteotomy seat 40 is placed into the bottom ofthe primary osteotomy site 20. Osteotomy seat 40 may have any desiredheight (to facilitate surface 16 cutting bone at the desired verticaldistance from the bottom of the site 20), and its diameter (althoughseat 40 need not be cylindrical) should be selected to snugly fit intothe bottom of the site 20. Seat 40 may be solid or hollow, or partiallysolid or hollow. The seat 40 includes a working surface 42 (in theillustrated embodiment surface 42 is concave hemispherical) that iscontacted by tip 18 of a burr as the burr is worked. Surface 42 ispreferably smooth. Also, the seat 40 may include anti-rotation featureson its sidewalls, such as ribs 44. Seat 40 may be made of any suitablematerial, including, without limitation, surgically suitable metals,nylons, and ceramics.

In operation, the seat 40 acts as a stop upon which (at surface 42) theburr is rotated, toggled, vibrated, or otherwise worked, therebyshielding the deep architecture of the osteotomy from inadvertent damagefrom direct motion of the burr. Although the embodiment of FIG. 9 showsa concave surface 42 for contact with a convex surface of tip 18, in analternate arrangement the tip 18 may be concave, and the surface 42convex. Indeed any suitable contour or shape may be used.

A threaded bore 46 may be provided through surface 42 to assist inplacement and removal of the seat 40. In particular, as shown in FIG.10, a threaded tool 48 is inserted into the bore 46 during insertion andremoval to place and remove the seat 40. The tool 48 is unscrewed, andthe seat 40 left at the bottom of the site 20, while the toggle burr isused to form the implant site. Although threads are illustrated, anysuitable mechanism or feature may be used to facilitate engagement ofthe seat 40 with an insertion/removal tool. As a non-limiting example,surface 42 may include one or more raised handle features thatfacilitate removal or insertion with a forceps.

Another embodiment is shown in cross sectional FIG. 11, in which theworking end 14 of a burr is coupled to an extension 52 and pivot member54 (which is a sphere in the illustrated example). Sphere 54 includes anattachment member 56 for attachment to the burr 50 at working end 14. Inthe particular example shown, attachment member 56 is a threaded shaft,for engagement with a matching threaded bore 58 in burr 50. Extension 52is a hollow shaft with an opening 60 at its burr end through whichattachment member 56 passes. Extension 52 is preferably convex at itsburr end 61 (although any suitable contour may be used) and engages withsurface 62 (which may be concave or any suitable contour). Sphere 54 mayinclude an internal hexagonal head recess 64 for receiving a hexagonaldriving tool for attachment and disengagement from the burr.

In operation of the embodiment of FIG. 11, the extension 52 acts as anextended tip or a stop to the burr 50 (surface 62 engaging with surface61), and pivot member 54 allows the burr to pivot on the extension 52.In the example shown, sphere 54 can rotate freely about it verticalaxis, but is constrained in its rotation about horizontal axes by thesize of hole 60. Thus, a drilling motion will not be limited, buttoggling will be limited by the size of the hole 60, as depicted in FIG.11 by the dashed borderlines 66. The height of extension 52 is selectedto facilitate surface 16 cutting bone at the desired vertical distancefrom the bottom of the osteotomy site, and its diameter (although itneed not be cylindrical) should be selected to snugly fit into thebottom of the site.

Although the embodiment of FIG. 11 shows a ball and socket arrangementof sorts, any suitable arrangement could be used to facilitate togglingand engagement of surfaces 61 and 62, such as a nylon connector cable, astainless steel flexible cable, or a universal hinge joint.

Following are examples of various uses of embodiments of the burrsdescribed herein.

When a cross-section of an edentulous site is presented in the patient,it is desired to minimize the bone removal toward the buccal or facialplate of bone in many instances. This occurs when there is a concaveshape to the maxilla in the anterior esthetic zone. In this instance aconcave implant embodiment, and thus the burr with a concave contouredsurface 16 would be the desired embodiments. This will preserve bonethickness in the labial wall and allow for immediate grafting in thecase of a fresh extraction socket. In many anterior maxillary incisors,the labial wall is very thin and can easily be perforated or damaged.This approach allows toggling without destroying the labial wall of thebone.

In the mandibular incisor area, the teeth are so narrow and thefacial/lingual dimension double the mesial distal dimension, that thisrequires a very narrow diameter primary osteotomy and then a narrowburr, with a concave contour to preserve the mesial distalintraradicular bone. This will also aid in prevention of nicking anadjacent root while drilling.

In the maxillary incisor area, the teeth in cross-section are softtriangulated and the burr can be worked to create an osteotomy thataccommodates this shape. A try-in of the implant will quickly identifyareas where bone needs to be removed and the burr reinserted toaccomplish this.

In the molar region, the burr may have a more definite convexity to thewall when required. The implant design will dictate the preferred burrshape. Often models will be available for many shapes based on osseousmorphology identified in the CT scans.

In practice, a kit of burrs having various sizes and shapes (includingvariously shaped attachable tips or sleeves for the attachableembodiments and variously shaped osteotomy seats) will be provided forflexibility in best preparing sites for different implants.

For completeness, the following two paragraphs are copied from theprovisional application of which this present application claims benefit(co-pending, prior filed U.S. provisional application No. 61/949,908,entitled “Eccentric Dental Implant System and Toggle Burr”, filed Mar.7, 2014). The only difference is that the original FIGS. 25-28 have beenrenumbered to FIGS. 12-15. Base member 108 referred to below correspondsto an implant base.

Referring now to FIGS. 12-15, an example burr 2502 is shown inaccordance with the principles of the present disclosure. In general,the burr 2502 may be coupled to a tool (not shown) that rotates the burrto shape features into bone, such as an osteotomy cavity 2504 as shownin top-down view in FIG. 15. Here, the shape of the osteotomy cavity2504 generally corresponds to the shape of the base member 108 (alsoshown in top-down view in FIG. 15). In the present example, the burr2502 includes a post 2506 terminated by a bulbous end 2508. The bulbousend 2508 is formed to include a grinding tip 2510 along with a pluralityof grinding ridges 2512 that are defined in a particular pattern orpitch. In one example, the burr 2502 may be coupled to a tool in amanner so that the tool may be held stationary while the burr 2502 isactuated or toggled through a particular angular range of motion asshown in FIG. 15.

In use, a pilot hole will first be drilled or cored to form a generallycylindrical opening or recess in the jawbone. Burr 2502 is placed withinthe opening. Typically, the outer diameter of burr 2502 will generallycorrespond to the cylindrical opening. Burr 2502 is rotated while alsobeing toggled with a desired motion. The angular motion of the burr 2502may be controlled to sweep through or around to any angle as desired tocarve or otherwise define the osteotomy cavity 2504. Additionally, oralternatively, the burr 2502 may be held in place at an angle as shownin FIG. 15, whereby the tool itself may be manipulated though anydesired range of motion to shape features into bone, similar toconventional tools used to shape features in to bone. Advantageously,the round/curved shape of the bulbous end 2508 may permit the apical endof the osteotomy to remain round and centered no matter what pattern onewould rock the toggle at the coronal (top) of the bone (e.g., oval,rectangle, triangle, etc.). That makes it very easy to match an alignedthrough-hole that the implant passes through. In some embodiments, theburr 2502 may be formed of stainless steel material. Other embodimentsare possible. In some embodiments, dimensions of the burr 2502 may be ina range from about 2.0 mm to about 8.0 mm in diameter inclusive, andvarious lengths to allow access in the mouth.

The particular embodiments and descriptions provided herein areillustrative examples only, and features and advantages of each examplemay be interchanged with, or added to the features and advantages in theother embodiments and examples herein. Moreover, as examples, they aremeant to be without limitation as to other possible embodiments, are notmeant to limit the scope of the present invention to any particulardescribed detail, and the scope of the invention is meant to be broaderthan any example. Also, the present invention has several aspects, asdescribed above, and they may stand alone, or be combined with some orall of the other aspects.

And, in general, although the present invention has been described indetail, it should be understood that various changes, alterations,substitutions, additions and modifications can be made without departingfrom the intended scope of the invention, as defined in the followingclaims.

What is claimed is:
 1. Apparatus for preparing a dental implant site ina jawbone, comprising: an osteotomy seat having a working surface; aburr having a shaft with a working end, wherein the working endcomprises: a cutting surface; and a smooth tip for contact with theworking surface.
 2. A method of preparing a dental implant site in ajawbone, comprising: forming an osteotomy site in a bone, the sitehaving a bottom and sidewalls; placing an osteotomy seat on the bottomof the osteotomy; and working a burr upon the osteotomy seat to widenthe osteotomy site by cutting the sidewalls.
 3. The method of claim 2,wherein working comprises toggling the burr.
 4. The method of claim 2,wherein working comprises vibrating the burr.
 5. The method of claim 2,wherein working comprises rotating the burr.
 6. The method of claim 2,wherein working comprises reciprocating the burr.
 7. The method of claim2, wherein working comprises toggling and vibrating the burr.
 8. Aninstrument for preparing a dental implant site in a jawbone, comprising:a shaft having a working end; the working end comprising: a cuttingsurface; and a smooth tip; and a vibrational source coupled to theshaft.
 9. An instrument for preparing a dental implant site in ajawbone, comprising: a shaft having a working end; the working endcomprising: a cutting surface; and a smooth tip, wherein the smooth tipis broad enough so as to prevent the creation of excessive depressionsin the jawbone when the smooth tip is in forced contact with thejawbone.
 10. An instrument for preparing a dental implant site in ajawbone, comprising: a shaft having a working end with a cuttingsurface; a pivot member coupled to the working end; and an extensionengaged with the pivot member, such that the working end pivots on theextension.